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Simple good habits can save you power without being too inconvenient.
Table of Contents Reference Links
Much of the power consumption of a computer is dependant on the processor chosen and then
the chipset design that goes with it. Laptops are usually of a more energy
efficient design to accommodate working on batteries. Laptop power supplies
have a lower consumption rate with ratings of 60 to 90 Watts being common.
Desktops will likely usually have 250 to 500 Watt power supplies although 1000
Watt supplies are available. The power supply rating relates to output wattage
while the input wattage will be higher. If you have a desktop add the power
consumption of the monitor which may add 30 to 120 Watts, remembering LCD uses
less power than a
| Settings | Consumption in watts |
|---|---|
| No power management | 100 |
| Screen power management on | 57 |
| Screen and drive power management on | 47 |
| Computer in full S3 sleep mode | 3 |
| Settings | Consumption in watts |
|---|---|
| No power management | 45 |
| Screen power management on | 30 |
| Screen and drive power management on | 20 |
| Laptop in full S3 sleep mode | 1.5 |
Suggestions: Apply computer power management to all computers. For laptops add power
management for battery mode. Choose Energy Star 4 computers with 80 Plus power supplies. A laptop connected to mains power
avoids extra power losses involved with recharging batteries.
Related Sections: Thin Client vs. Desktop 80 Plus Power Supplies Energy Star 4 BIOS settings New Low Power Processors
Local Assistance: Computer Energy Calculator Computer Power Consumption Calculator
References for further information 1 45 46 47 126
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Thin Clients are devices that connect to a server and run a virtual computing
session, alleviating the need for a desktop computer on each desk. At the thin
client it receives screen information from a server and sends keyboard and
mouse changes. A new feature of thin clients is the inclusion of decent screen
resolution (1600 x 1200), multimedia performance and VOIP capabilities. A thin
client uses about 10 Watts. Add approximately 30 Watts for a LCD screen when in
use, with 1 watt for standby. A thin client can operate Linux, Windows XP, Windows Vista or
Windows 7 using the same hardware thus avoiding desktop upgrade cycles. The
average bandwidth is 25 kb /second which will suit dial up connections. A
server processor can support 26 to 42 thin clients. A blade server could
support 100’s of thin client users. Your memory usage is centralised and common
memory blocks are not duplicated, so you’ll only need 512 kB per Windows XP for
example. The overall consumption expected for 20 users changes from 4300 Watts
with desktops to 1840 Watts with thin clients and a server. Auxiliary benefits
are less heat; no moving parts to break; light weight as each thin client
weighs around 500 grams; compact enough to clip to back of an LCD screen; easy
to deploy even remotely; just plug it in; better security as data held in one
place only; the
Suggestions: Useful for computer lab rooms, libraries and areas where common
applications are used by many.
Related Sections: Laptop vs. Desktop Virtual Computing with Storage Area Network VOIP
Local Assistance: Thin Clients with Hosted Server Desktop, Thin Client, Nettop review
References for further information 47 48
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A virtual computer (virtual machine or VM) is a representation of a full computer with
hardware the configuration held within two files. Many virtual computers can be
run on a single physical computer simultaneously with ratios of 10:1 possible.
There are limitations on how many VM’s can be successfully run concurrently on
a computer and there is no redundancy in case of hardware failure. Having
multiple physical computers connected to a single Storage Area Network (
| Company | Servers Before | Servers After |
|---|---|---|
| Tourism |
70 | 35 |
| Stirling |
54 | 7 |
| 85 | 20 | |
| Orica | 40 | 10 |
| Townsville (old) Council | 100 | 53 |
Suggestions: Consider VM for servers running 1-15% utilisation average,
consider consolidating old server functions into fewer modern servers or
blades.
Related Sections: Thin Client vs. Desktop Network Attached Storage
Local Assistance: Modern Virtual Computing
References for further information 49 50 120
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80 Plus is a standard for computer power supplies than have a minimum 80% efficiency at 20%, 50% and 100% load and over 0.9 power factor. Standards above plain 80 Plus is Bronze, Silver and Gold over 90% efficient. A saving in power in the order of 28% is possible by using an 80 Plus standard power supply. You will save approximately 30% of the cooling costs associated with the computer. Some maintenance costs are reduced due to there being less heat in the computer. The extra investment for an 80 Plus power supply is returned in less than 1 year. There are over 700 power supplies than pass the 80 Plus standard. See reference links for an online calculator and suppliers.
| Computer Load | Power In ( |
Power In ( |
Year Consumption (kWh) | Year Consumption (kWh) | Year Savings |
|---|---|---|---|---|---|
| 60% efficient supply | 85% efficient supply | 250 x 9 hr days (60%) | 250 x 9 hr days (85%) | kWh | |
| 100 | 166.67 | 117.65 | 375.00 | 264.71 | 110.29 |
| 200 | 333.33 | 235.29 | 750.00 | 529.41 | 220.59 |
| 300 | 500.00 | 352.94 | 1125.00 | 794.12 | 330.88 |
| 400 | 666.67 | 470.59 | 1500.00 | 1058.82 | 441.18 |
| 500 | 833.33 | 588.24 | 1875.00 | 1323.53 | 551.47 |
Add standby consumption for non operational periods.
Use power saved value from first table. Multiple results by the number of computers in the workplace.
| Power kWh Saved / $ kWh | Local cost of electricity in dollars per kilowatt hour (kWh) | ||||||||
|---|---|---|---|---|---|---|---|---|---|
| 0.08 | 0.1 | 0.12 | 0.14 | 0.16 | 0.18 | 0.2 | 0.22 | 0.24 | |
| 110.29 | $8.82 | $11.03 | $13.23 | $15.44 | $17.65 | $19.85 | $22.06 | $24.26 | $26.47 |
| 220.59 | $17.65 | $22.06 | $26.47 | $30.88 | $35.29 | $39.71 | $44.12 | $48.53 | $52.94 |
| 330.88 | $26.47 | $33.09 | $39.71 | $46.32 | $52.94 | $59.56 | $66.18 | $72.79 | $79.41 |
| 441.18 | $35.29 | $44.12 | $52.94 | $61.77 | $70.59 | $79.41 | $88.24 | $97.06 | $105.88 |
| 551.47 | $44.12 | $55.15 | $66.18 | $77.21 | $88.24 | $99.26 | $110.29 | $121.32 | $132.35 |
Suggestions: Look for 80 Plus logo for all new desktop / server computer purchases.
Consider the expected 1 to 30 watts of power supply consumption in standby
mode. Servers with redundant power supplies have quite high standby power consumption
in the order of 10 to 200 watts.
Related Sections: Power Factor Correction Laptop vs. Desktop Measurement USB Power board New Low Power Processors
Local Assistance: Computer Power Consumption Calculator
References for further information 1 25 51 144
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Energy Star 4 is a standard relating to computers relate to the maximum power consumption for various activities. Governments are pushing for this to be the standard for new computer hardware. Their requirements usually include an 80 Plus power supply with computer power management enabled. Windows Server 2008 and Windows 7 have more power management options available for control.
| Computer | Idle | Sleep | Standby |
|---|---|---|---|
| Desktop | 50 Watts | 4 Watts | 2 Watts |
| Notebook | 14 Watts | 1.7 Watts | 1 Watt |
Power
Management settings needed as part of Energy Star 4 Standard are:
Suggestions: Look for computers with Energy Star 4 or 5 labels and buy them as a
preference. Turn on existing computers power management options.
Related Sections: 80 Plus Power
Supplies BIOS settings
Local Assistance: Computer Power Consumption Calculator
References for further information 1 23 52 120 121
Table of Contents Reference Links
The Voice on Internet Protocol allows you to implement telephony over your computer
network. Calls that run over your own network are free of telephony carrier
charges. One IP based PABX can work 1000’s of IP extensions across an
Suggestions: See if VOIP suits you before adding trunks or moving locations or if
long distance phone charges are too high
Related Sections: Thin Client vs. Desktop Video Conferencing
Local Assistance: VOIP detailed Presentation VOIP with remote provider
References for further information 53
Table of Contents Reference Links
Video conferencing is now possible across the Internet free of charge, excluding your
Internet bandwidth charges.
Suggestions: Try it
Related Sections: VOIP
Local Assistance: VOIP detailed Presentation VOIP with remote provider
References for further information 54 55
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This technology basically connects a hard disk to your computer network to allow full time shared access for your network users. This technology will suit small to medium networks where a dedicated server may not be needed. NAS can also include feature file sharing, backup, web server, database server, print server and multimedia server functions. The advantage of NAS devices is that it can run on far less power than a dedicated server, for example it uses 17 watts in operation and 6 watts in sleep mode. Other functions possible include remote access across the Internet to your NAS this is useful for connecting to home storage from any location. NAS devices usually come in 1, 2, 4 drive enclosures. RAID configurations are possible for redundancy. NAS devices can replicate from each other for backup purposes. Not adding another server dedicated server on your network may save you $1000 per year in electricity.
Suggestions: Consider NAS for department storage, special projects, Virtual Machine
development, and centralised backups. For larger scenarios consider
Related Sections: Virtual Computing with Storage Area Network
Local Assistance: External Storage Presentation
References for further information 56
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There is a class of processors that use much less power than regular laptops. They can be found
in the new generation of ultra light laptops, smart phones and dedicated
devices such as digital set top boxes. Processors in this class include the
Intel Atom (4 watts), Via Eden (2.5 to 7 watts) and the
Suggestions: Consider future requirements versus processors available and consider
choosing a new generation low powered processor. Enable computer power
management. Turn off wireless networking when not required.
Related Sections: Thin Client vs. Desktop
Local Assistance: Computer Power Consumption Calculator
References for further information 57 58 128 129
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A simple way to control the power of the many devices connected to a computer is to use
a
Suggestions: As an alternative turn off all computer equipment manually at the wall
when finished
Related Sections: Standby
loads table
References for further information 7 131 149
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BIOS relates to how you computer motherboard is configured to work with computer hardware. There are certain features on motherboards that need to be turned on to get the maximum effect from computer power management. These include:
Older computers will have most of the power management features turned off by default. Motherboard default specifications are improving all the time especially to comply with Energy Star 4. The BIOS features need to work with the operating system computer power management system being enabled to achieve good power savings. Compare the power usage of a desktop or laptop running at full power all day relative to a few watts in sleep mode. In the case of networked computers power management can be defined in group policies with some software help some of which are listed in the references. Specialised computer power management software can save approximately 38% of computing electricity by using advanced features such as to sleep or shut down computers remotely as required.
Suggestions: Review your BIOS manual to see what energy saving adjustments can be
made. Buy Energy Star 4 computers as most adjustments will be already enabled.
Turn on computer power management options.
Related Sections: Energy Star 4 Laptop vs. Desktop
References for further information 59 60 61
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